Republican and Democratic lawmakers expressed confidence Sunday that a deal to avert the fiscal cliff could be reached, as the man who will need to sign off on the agreement looked toward a higher authority for additional help.

Touring a Buddhist monastery in Bangkok, President Barack Obama was overheard discussing crucial talks to stave off the looming tax hikes and spending cuts with state secretary Hillary Clinton and their monk guide.

"We're working on this budget, we're going to need a lot of prayer for that," he joked, prompting laughter from all concerned.

But back in the US, the mood was a little more optimistic. In a series of interviews Sunday, representatives of both parties appeared to acknowledge a willingness to find compromise, even if significant hurdles remain.

Congress has until the end of the year to hammer out a compromise or risk triggering the so-called fiscal cliff – a toxic mix of swingeing cuts and tax increases that could derail the still delicate US economic recovery.

Speaking on CNN's State of the Union on Sunday, Dick Durbin, the second highest ranking Democrat in the Senate, said: "What I hear is a perceptible change in rhetoric from the other side."

He added: "And what it is is an invitation for our side to basically sit down and say: 'What can we do for this country?'"

Likewise, senior Republican House representative Tom Price, appeared to suggest that progress had been made. He and his colleagues recognised the need to generate more in tax revenue, he told CNN.

"The two sides have identified the tax revenue that we're willing to discuss, and now it's time to talk about spending reductions," Price, a leading conservative, said.

But the road ahead is unlikely to be easy. The gulf remains between the two parties when it comes to individual tax increases on the wealthy.

Price stood by the argument that such a move would lead to job losses. Instead, the Republicans want to generate more revenue through the closing of loopholes. In addition, any uptake in tax needed to be paired with spending cuts.

Meanwhile, Obama was repeatedly warned that he will not sign off on a deal that doesn't include a raise in the tax rate for America's super rich.

Most Republican lawmakers have signed a pledge, thrust under their nose by conservative lobbyist Grover Norquist, that in effect handcuffs them to a "no tax increase" policy.

Getting some conservatives to break that promise may take more than a simple appeal to a higher authority, Obama may find.